The present invention relates to the field of automated manufacturing apparatus and, more specifically, to a part positioning apparatus and method for manipulating a small part or component of a product to place it in a desired position and orientation in preparation for a subsequent product assembly operation.
In the interest of improving efficiency and reducing costs, programmable robotic part-handling devices are being incorporated into automated production lines. The appeal of a robotic device is that it can be programmed to do various tasks and it does not have to be dedicated to a particular product assembly. Thus, a robotic device may be viewed as a generic type of automated manufacturing tool that does not become obsolete when the product or manufacturing process changes.
In one type of product assembly operation, a robotic part-handling device picks up a part and places it on the assembly. Generally, the part must be precisely positioned and oriented at a pick up station for a robotic device to successfully grasp it and transfer it to the assembly.
To further reduce manufacturing costs, it is highly desirable to provide a generic part positioning apparatus that can be used with a variety of different parts rather than having to provide a dedicated machine or tool that is limited to handling only one particular part.
One type of generic part positioning apparatus known in the art comprises a turntable having a part supporting stage thereon which is movable in two directions along X and Y axes. A part to be picked up by a robotic device is placed on the stage which is moved in the X and Y directions to locate the part in a desired pick up area or zone in a horizontal X-Y plane. Then, the turntable is rotated about a vertical axis centered in the pick up area until the part achieves a desired angular orientation .theta. or direction in the plane for pick up. Generally, this type of apparatus employs a vision system or photodetector array for sensing the X, Y and coordinates of the part. This information is fed to a computer based control system which automatically operates the linearly movable stage and turntable. Typically, a large amount of data has to be generated and processed during the course of the position sensing and adjustment cycle which tends to make the control system complex and expensive. Also, the X-Y stage mechanism is expensive because it requires highly accurate and repeatable actuators or drivers for precisely adjusting the locations of the various movable components. For a representative example of this type of positioning apparatus, reference may be had to U.S. Pat. No. 4,457,664.
Thus, there is a need for a positioning apparatus that is generic in nature, i.e., it may be used with a variety of different parts without substantial modification, and is less complex than the relatively expensive type of positioning apparatus described above that uses a movable X-Y stage mounted on a turntable.
As will be described later in detail, the present invention provides a generic type of part positioning apparatus which includes a specially shaped part receptacle that is subjected to a vibratory force for facilitating movement of a part therein to a designated area in a horizontal plane. The use of vibratory force to move or facilitate movement of a part for positioning and/or orientation purposes is known in the art. However, this method generally is employed in conjunction with a dedicated part positioning apparatus that is specifically designed for a particular part. For representative examples of such apparatus, see U.S. Pat. Nos. 4,436,479; 4,079,830; 3,868,759; 2,807,350, and 2,725,971.
Therefore, it is an object of the present invention to provide a part positioning apparatus that may be used with a variety of different parts yet is simple in its construction and is easy to use.
Another object is to provide such a part positioning apparatus which eliminates the need for a linearly movable X-Y stage to locate a part in a designated area of a horizontal plane.
Yet another object is to provide such a part positioning apparatus which positions a part with respect to X and Y axes and rotates the part to provide a desired angular orientation .theta. or direction.
Still another object is to provide such a part positioning apparatus which may be used to position and orient a part for pick up by a robotic part handling device.
Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.